which represents three groups of vehicles lining
up in a queue. From [1]}, for
any \(\rho ^{,} \in L^{1}(\mathbb {R};[0,1])\) ,
the Cauchy problem with initial datum \(\rho _{0}\) 
allows a unique solution \(\rho = \rho (t,x)\) ,
reaching values in \([0,1]\) . The qualitative
behaviors of the solution are rather different
in the two situations in (REF ). The
expected big oscillations in the vehicular
density caused by the backward-looking case can be
seen in Figure REF  (as opposed to the
far more reasonable behavior
in the forward-looking scenario in Figure REF ).
The structure of the numerical
solutions presented here are in particularly good
agreement with [1]}. We will also present in Table REF  an error analysis, so that it is possible to observe that our method presents first-order accuracy behavior.
<FIGURE><FIGURE><FIGURE><TABLE>